Shigeru Tamaki

The structures of 3d-transition metals in the liquid state

Abstract The structures of 3d-transition metals (Ti, V, Cr, Mn, Fe, Co, Ni and Cu) in the liquid state have been systematically examined by X-ray diffraction at temperatures above their melting points. In terms of the usual Fourier analysis, the atomic radial distribution functions were obtained from which interatomic distance and coordination number were estimated.

Structural study of molten silver halides by neutron diffraction

The Structure factors of molten AgCl, AgBr and AgI have been obtained by neutron scattering measurements at two different temperatures in order to investigate the local structure and its temperature dependence. The partial structural parameters such as a partial coordination number and an inter ionic distance have been determined by curve fitting analysis. Molten silver halides are found to have tetrahedral coordination of the local order near the melting points. The local order for molten AgCl and AgBr is broken with increasing temperature, while that for molten AgI is preserved even at high temperature. This suggests that the bonding in molten AgI has more covalent character than that in molten AgCl and AgBr.

Magnetic Susceptibilities of liquid Te Alloys

The magnetic susceptibilities of the liquid Ga–Te, In–Te and Tl–Te systems have been measured as a function of concentration and temperature. Curves of the susceptibilities of these alloys for all concentrations show rather a large deviation from the linearly interpolated ones at the compositions near Ga 2 Te 3 , In 2 Te 3 and Tl 2 Te. From these results, the range of the localization of electrons is also discussed.

The partial structure factors of liquid Ni–Si alloys

Abstract A detailed analysis of X-ray scattering intensity of liquid Ni–25, 50 and 75 at. % Si alloys has been carried out by X-ray diffraction with anomalous scattering technique. The scattering powers of these alloys were changed by the anomalous scattering by the Ni atom of Mo, Cu and Co radiations and the three partial structure factors required to characterize a binary alloy were estimated. It is found that they are approximately independent of the concentration of the alloys and the Ni and Si atoms act to a first approximation as hard spheres in liquid Ni–Si alloys.

Structures of Molten CuCl, CuBr and CuI

The structures of molten CuCl, CuBr and CuI have been measured at two temperatures, using the neutron diffraction. The structure factors of molten CuI and CuBr show a distinct prepeak at about 0.9 A -1 . These peaks may be caused by a kind of chemical ordering effect. The information of partial structures are estimated from the total pair distribution functions and the total radial distribution functions using the Davidon-Fletcher-Powell method. In molten CuCl, the first peak positions of the partial distribution functions agreed with those obtained by the isotope enrichment method.

The Characteristic Temperature Dependence of the Structure of Liquid Tellurium by Neutron Diffraction

The neutron diffraction study of liquid tellurium has been carried out to reveal the origin of characteristic temperature dependence of various properties related to the atomic scale structure. The temperature dependence of measured structural functions of liquid tellurium could be explained by a gradual transition from the two-fold coordinated ordering (non-metallic) to the three-fold coordinated one (metallic). Thermodynamic properties of liquid tellurium have also been appeared to be consistent with the present interpretation for the change in structure with increasing temperature.

Specific heat of liquid In-Te alloys

The temperature and composition dependence of the specific heat in liquid In-Te alloys, measured with adiabatic calorimeter, are reported. The specific heat isotherms around the composition of In2Te3 are anomalously large above the liquidus temperature and they tend to be small at very high temperatures. The large specific heats and their temperature dependences are satisfactorily explained in terms of the partial dissociation of compound formation with increasing temperature. The required molar energy for the dissociation from semiconducting to metallic states in liquid Te is about 3.31 kcal mol-1 and that in liquid In2Te3 is 4.21 kcal mol-1.

The structure analysis liquid Sb2Se3 by neutron diffraction

Abstract The radial distribution analysis of liquid Sb2Se3 at 670, 720 and 770°C is carried out by the neutron diffraction method. A small but apparent maximum is found at K = 1.2 A −1 in the structure factor. The interatomic distance and the coordination number are 2.74 A and 2.84 respectively, at 670°C. These results suggest that intramolecular bonds in the crystalline Sb2Se3 remain unbroken in the liquid state. The general feature of the structure factor and the distribution function for liquid Sb2Se3 is similar to that for the amorphous state. However, it is clear that the liquid phase tends to have a similar atomic arrangement to that of liquid tellurium.

The structure of rare earth metals in the liquid state

Abstract The structure of liquid rare earth metals (So, La, Ce, Pr, Eu, Gd, Tb and Yb) have been systematically examined by X-ray diffraction at temperatures above their melting points. The structure factors of liquid La, Ce, Pr, Eu and Yb were temperature insensitive in the presently available experimental temperature range. In terms of the usual Fourier analysis, the atomic radial distribution functions were obtained from which interatomic distances and coordination numbers were estimated.

Localized Impurity States in Liquid Metals: Electrical Properties of 3d-Transition Metals in Liquid Tin

Electrical resistivities and thermopowers of 3 d -transition metals in liquid tin are measured. The data are analized under the concept of virtual bound state. The number of localized electron of Ni, Co and Fe in liquid tin is estimated using the experimental data. From the thermopower, the state density of the virtual bound state at Fermi level and the effective contribution of Coulomb and exchange interaction U +4 J are estimated.